Microsleeps (or microsleep episodes) become extremely dangerous when occurring during situations which demand constant alertness, such as driving a motor vehicle or working with heavy machinery. People who experience microsleeps usually remain unaware of them, instead believing themselves to have been awake the whole time or to have temporarily lost focus.

One example is called "gap driving": from the perspective of the driver, he drives a car, and then suddenly realizes that several seconds have passed by unnoticed. It is not obvious to the driver that he was asleep during those missing seconds, although this is in fact what happened. The sleeping driver is at very high risk for having an accident during a microsleep episode.

Many accidents and catastrophies have resulted from microsleep episodes in these circumstances.[2] For example, a microsleep episode is claimed to have been one factor contributing to the Waterfall train disaster in 2003; the driver had a heart attack and the guard who should have reacted to the train's increasing speed is said by his defender to have microslept.

There is little agreement on how best to identify microsleep episodes. Some experts define microsleep according to behavioral criteria (head nods, drooping eyelids, etc.), while others rely on EEG markers. One study at the University of Iowa defined EEG-monitored microsleeps in driving simulation as "a 3-14 second episode during which 4-7 Hz (theta) activity replaced the waking 8-13 Hz (alpha) background rhythm."[3]

In an episode of Microsleep, a patient was hooked up to an EKG while an echocardiogram was performed. After the patient entered sleep his heart rate increased from 65 beats to 130 beats during a 1-4 second period of time and returned to normal at second 5, upon becoming fully awake. The patient describes that he was scared of the probe that was doing an ultrascan on his heart on the lower left part of his chest. The study was done at Banner Health Good Samaritan Medical Center in Phoenix, Arizona on January 12, 2010 and not under the care of a medical doctor but during a training exercise.

Microsleep is a very short sleep that occurs when people are awake. It can last from under a second to about 30 seconds.[1] It may happen as a result of sleep deprivation, fatigue, sleep apnea, narcolepsy, or hypersomnia. Microsleeps can occur at any time. Most of the time, they do so without warning. When people have a microsleep during conversation, they may lose track of the subject that was talked about.

Microsleep can be extremely dangerous in situations when people drive a car, work on a machine or otherwise need to stay alert. People with microsleeps usually are not aware of them. They instead believe that they were awake all the time. One example is called "gap driving": a person is driving a car and suddenly realizes that several seconds have passed by unnoticed. The driver does not feel that she or he has been asleep during those missing seconds, although this is in fact what happened. The sleeping driver is at very high risk for having an accident during microsleep.

Many accidents and catastrophes have resulted from microsleep episodes in these circumstances.[2] For example, a microsleep episode is claimed to have been one factor contributing to the Waterfall train disaster in 2003; the driver had a heart attack and the guard who should have reacted to the train's increasing speed is said by his defender to have microslept.

References

↑ International Classification of Sleep Disorders Diagnostic and Coding Manual